Regularities of Hydrogen Evolution on Cathodes Modified with Mo-Co Alloy

摘要

Regularities of the cathodic evolution of hydrogen from 30% KOH solution on titanium and cobalt electrodes, the surfaces of which are modified with an electrolytic Mo-Co alloy containing 85-88% molybdenum, are studied. Hydrogen evolution overpotentials on the modified electrodes are shown to be substantially lower than those on the original electrodes, which is related to the catalytic effect of the alloy on the electrode process, as well as the noticeably more developed surface of the modified electrode. The depolarization reached depends on the nature and surface state of the cathodic base metal where the alloy is applied. The slopes of Tafel segments of the polarization curves of hydrogen evolution on modified electrodes are determined at electrolyte temperatures of 20, 35, 50, and 65°C, and the actual activation energy is calculated. Volmer-Tafel, Volmer-Heyrovsky, and Tafel-Horiuchi mechanisms are shown to provide a reasonable description of the hydrogen evolution.